Authors:
Stuart Reges, Marty Stepp
Chapter:
Linked Lists
Exercise:
Exercises
Question:16 | ISBN:9780136091813 | Edition: 2
Question
Write a method called removeRange that accepts a starting and ending index as parameters and removes the elements at those indexes (inclusive) from the list. For example, if a variable list stores the values [8, 13, 17, 4, 9, 12, 98, 41, 7, 23, 0, 92] , the call of listRange.removeRange(3, 8); should remove values between index 3 and index 8 (the values 4 and 7 ), leaving the list of [8, 13, 17, 23, 0, 92] . The method should throw an IllegalArgumentException if either of the positions is negative. Otherwise you may assume that the positions represent a legal range of the list (0 <= start <= end < size).
Add the above method to the LinkedIntList class from this chapter.
Answer
Implementation of removeRange method:
public void removeRange(int start, int end)
{
if(start < 0 || end < 0)
throw new IllegalArgumentException();
ListNode previous = null;
ListNode current = front;
int index = 0;
while(current != null && index < start)
{
previous = current;
current = current.next;
index++;
}
while(current != null && index <= end)
{
if(previous == null)
{
front = front.next;
previous = null;
current = front;
}
else
{
previous.next = current.next;
current = previous.next;
}
index++;
}
}